Last updated on March 31st, 2022
Rainwater harvesting system cost guide
A rainwater harvesting system (RHS) usually involves the collection of rainwater on the roof, using a storage tank and pumping to direct the water where it’s needed in the home. In this guide, we’ll look at the average cost of a rainwater harvesting system in the UK.
A rainwater harvesting system (RHS) usually involves the collection of rainwater on the roof, using a storage tank and pumping to direct the water where it’s needed in the home. While not usually used for drinking, water from an RHS can be used for flushing toilets, supplying washing machines and watering plants in the garden.
Rainwater harvesting can reduce your dependence on water from the mains supply. This potentially means smaller water bills. It’s also environmentally beneficial and in some cases can reduce flood risk (as run-off water goes into the RHS, not the ground).
In this guide, we’ll look at the average cost of a rainwater harvesting system in the UK.
How much does a rainwater harvesting system cost?
The cost of a rainwater harvesting system for domestic use depends on the kind of system you get. At the very simplest level, you can get a basic water butt from as little as £70. Alternatively, one with a water pump to connect it to your property for around £750.
| Rainwater harvesting system | Low cost | High cost | Average cost |
|---|---|---|---|
| Water butt | £70 | £750 | £410 |
| Rainwater harvesting system - domestic | £2,000 | £3,000 | £2,500 |
| Rainwater harvesting system - commercial | £2,500 | £12,000 | £7,250 |
| Installation costs (for domestic RHS) | £3,000 | £9,000 | £6,000 |
Our costs are ballpark averages – get a local tradesperson to quote now
For a fully functioning domestic RHS, the cost will include the price of the tank, filter, pump and pipes, control unit and connectors. The average cost of rainwater harvesting systems for home use is around £2,500. This doesn’t however include installation.
Rainwater harvesting system installation cost
Now that you’ve bought your new RHS, you need a professional contractor to install it for you. Depending on the complexity of the plumbing and pipework, plus access requirements, this can cost upwards of £3,000 for domestic systems.
Cost of rainwater harvesting system for businesses
A RHS for commercial use is likely to consist of a larger, more advanced system. However, smaller businesses can potentially install systems at a similar cost to domestic ones.
For larger organisations, the average commercial rainwater harvesting system cost could be as much as £12,000.
FAQs
Where should I put the tank for my rainwater harvesting system?
Water collection tanks for rainwater harvesting are often installed just below the roof, to collect run-off. But bear in mind that tanks in this location will usually need protection from freezing.
If you’re installing the tank on the roof itself, remember that they can sometimes be unsightly as well as very heavy.
Another option is to install your tank below ground. However, excavation can be expensive and isn’t always possible on every site.
How much rainwater could I collect?
For most homes, a tank with a storage capacity of 1,500 to 2,000 litres should be adequate. This should give you enough water for your washing machine and to flush the toilet.
To work out which size tank you need, a good rule of thumb is to start at 5% of the available annual rainfall.
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